This study is designed to provide histologic evidence in humans of the potential for regeneration of periodontal tissues including alveolar bone, cementum and a functional periodontal ligament in patients whose attachment apparatus has been destroyed by periodontal disease. Patients selected for this study will have teeth designated for extraction by the Oral Diagnosis Department at the University of Maryland Dental School. Condemned teeth will have associated intrabony defects with visible calculus on the root surface. In each of the three phases of the investigation, the most apical level of calculus on the root will serve as a histologic reference point to measure regeneration. In Part I, attempts will be made to initiate repair of the intrabony defect by flap curettage, crown removal (coronectomy) and submersion of the vital root below the mucosa. In Part II, demineralized freeze-dried bone allograft will be placed in debrided defects to determine if this material will initiate or enhance regeneration of intrabony defects associated with submerged roots. Part III will evaluate potential for repair of intrabony defects in nonsubmerged roots with and without the use of demineralized freeze-dried bone allograft. Biopsies will be obtained and regeneration will be evaluated histologically. Patients will be provided temporary prosthetic treatment during the healing phase and on completion of the study they will be provided complete restorative care and maintenance. The results of the study will have a major impact on the direction of research in new attachment procedures in the future. It is designed to answer several controversial questions related to the clinical practice of periodontics and will result in improved patient care.